U.S. patent application number 11/842802 was filed with the patent office on 2009-02-26 for method and apparatus for optimization of sigcomp udvm performance.
This patent application is currently assigned to QUALCOMM Incorporated. Invention is credited to Manoj M. Deshpande, Adrian Escott, Kirti Gupta, Ramachandran Subramaniam.
Application Number | 20090055899 11/842802 |
Document ID | / |
Family ID | 40383392 |
Filed Date | 2009-02-26 |
United States Patent
Application |
20090055899 |
Kind Code |
A1 |
Deshpande; Manoj M. ; et
al. |
February 26, 2009 |
METHOD AND APPARATUS FOR OPTIMIZATION OF SIGCOMP UDVM
PERFORMANCE
Abstract
A mobile communication system that utilizes multiple access
technologies achieves multiple session registrations by deriving a
plurality of extended unique device identifications from a specific
unique device identification (e.g., private user identification
(PIID) stored on a subscriber identity module (SIM)) assigned to a
user equipment. Each of the plurality of extended unique device
identifications have the benefit of allowing multiple registrations
with one or more access networks while allowing a home subscriber
system to detect the one unique device identification embedded in
the extended unique device identifications for authentication
purposes. Thereby, a large population of deployed UEs and access
network infrastructure may benefit without replacement by allowing
a UE to maintain session continuity when transitioning between
access networks, to select a preferred access technology when in
overlapping coverage areas without session interruption, or to
maintain multiple sessions (e.g., simultaneous Voice over IP (VoIP)
and media streaming) with different access networks.
Inventors: |
Deshpande; Manoj M.; (San
Diego, CA) ; Escott; Adrian; (Reading, GB) ;
Gupta; Kirti; (San Diego, CA) ; Subramaniam;
Ramachandran; (San Diego, CA) |
Correspondence
Address: |
QUALCOMM INCORPORATED
5775 MOREHOUSE DR.
SAN DIEGO
CA
92121
US
|
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
40383392 |
Appl. No.: |
11/842802 |
Filed: |
August 21, 2007 |
Current U.S.
Class: |
726/4 ;
370/352 |
Current CPC
Class: |
H04L 65/80 20130101;
H04L 65/1069 20130101; H04L 65/1083 20130101; H04L 65/1073
20130101; H04W 36/0022 20130101 |
Class at
Publication: |
726/4 ;
370/352 |
International
Class: |
G06F 7/04 20060101
G06F007/04; H04L 12/66 20060101 H04L012/66 |
Claims
1. A method for supporting multiple session registrations of a data
packet protocol for a user equipment assigned a unique device
identifier, comprising: receiving a first session initiation
protocol (SIP) registration request from a user equipment
comprising a unique device identifier for the user equipment
appended to one of a plurality of registration extensions;
detecting the unique device identifier, authenticating that the
unique device identifier is a subscriber, and responding with a
network address to enable a first data packet protocol session;
receiving a second SIP registration request from the user equipment
comprising the unique device identifier appended to another of the
plurality of registration extensions; and detecting the unique
device identifier, authenticating that the unique device identifier
is a subscriber, and responding with a second network address to
enable a second data packet protocol session.
2. The method of claim 1, wherein receiving the first and second
SIP registration requests further comprising establishing multiple
session through a single SIP proxy server.
3. The method of claim 1, further comprising: establishing the
first SIP registration with a first access network; and
establishing the second SIP registration with a second access
network.
4. The method of claim 3, further comprising: accessing a
preference for receiving a communication service from the second
access network; establishing the first SIP registration with the
first access network in response to the second access network being
unavailable; and establishing the second SIP registration with the
second access network when available while maintaining session
continuity.
5. The method of claim 3, further comprising: establishing the
first SIP registration with the first access network to receive a
communication service when the first access network is available;
establishing the second SIP registration with the second access
network when available to receive the communication service when
the second access network is available; and maintaining
communication service continuity by selectively switching between
the two active SIP registrations.
6. The method of claim 3, further comprising: establishing the
first SIP registration to a cellular circuit switch; and
establishing the second SIP registration to a wireless local access
network.
7. The method of claim 1, further comprising: receiving a first
multiple registration request at a first SIP proxy server; and
appending a multiple registration extension to the unique device
identifier and transmitting to an SIP registrar server that detects
the unique device identifier.
8. The method of claim 7, further comprising: receiving a second
multiple registration request at a second SIP proxy server;
responding with a failure message to the user equipment; receiving
the second SIP registration request from the user equipment
comprising the unique device identifier appended to another of the
plurality of registration extensions at the second SIP proxy server
and forwarding to the SIP registrar server; and detecting the
unique device identifier and multiple registration at the SIP
registrar server.
9. At least one processor configured to support multiple session
registrations of a data packet protocol for a user equipment
assigned a unique device identifier, comprising: a first module for
receiving a first session initiation protocol (SIP) registration
request from a user equipment comprising a unique device identifier
for the user equipment appended to one of a plurality of
registration extensions; a second module for detecting the unique
device identifier, authenticating that the unique device identifier
is a subscriber, and responding with a network address to enable a
first data packet protocol session; a third module for receiving a
second SIP registration request from the user equipment comprising
the unique device identifier appended to another of the plurality
of registration extension; and a fourth module for detecting the
unique device identifier, authenticating that the unique device
identifier is a subscriber, and responding with a second network
address to enable a second data packet protocol session.
10. A computer program product, comprising: a computer-readable
medium comprising: a first set of codes for causing a computer to
receive a first session initiation protocol (SIP) registration
request from a user equipment comprising a unique device identifier
for the user equipment appended to one of a plurality of
registration extensions; a second set of codes for causing the
computer to detect the unique device identifier, authenticating
that the unique device identifier is a subscriber, and responding
with a network address to enable a first data packet protocol
session; a third set of codes for causing the computer to receive a
second SIP registration request from the user equipment comprising
the unique device identifier appended to another of the plurality
of registration extension; and a fourth set of codes for causing
the computer to detect the unique device identifier, authenticating
that the unique device identifier is a subscriber, and responding
with a second network address to enable a second data packet
protocol session.
11. An apparatus for supporting multiple session registrations of a
data packet protocol, comprising: means for receiving a first
session initiation protocol (SIP) registration request from a user
equipment comprising a unique device identifier for the user
equipment appended to one of a plurality of registration
extensions; means for detecting the unique device identifier,
authenticating that the unique device identifier is a subscriber,
and responding with a network address to enable a first data packet
protocol session; means for receiving a second SIP registration
request from the user equipment comprising the unique device
identifier appended to another of the plurality of registration
extension; and means for detecting the unique device identifier,
authenticating that the unique device identifier is a subscriber,
and responding with a second network address to enable a second
data packet protocol session.
12. An apparatus for supporting multiple session registrations of a
data packet protocol, comprising: a first receiver for receiving a
first session initiation protocol (SIP) registration request from a
user equipment comprising a unique device identifier for the user
equipment appended to one of a plurality of registration
extensions; a server for detecting the unique device identifier in
the first SIP registration request, authenticating that the unique
device identifier is a subscriber, and responding with a network
address to enable a first data packet protocol session; a second
receiver for receiving a second SIP registration request from the
user equipment comprising the unique device identifier appended to
another of the plurality of registration extensions; wherein the
server detects the unique device identifier in the second SIP
registration request, authenticates that the unique device
identifier is a subscriber, and responds with a second network
address to enable a second data packet protocol session.
13. A method for initiating multiple session registrations of a
data packet protocol for a user equipment assigned a unique device
identifier, comprising: sending a first session initiation protocol
(SIP) registration request comprising a unique device identifier
for the user equipment appended to one of a plurality of
registration extensions; utilizing a first data packet protocol
session in response to an access network detecting the unique
device identifier, authenticating that the unique device identifier
is a subscriber, and responding with a network address to enable
the first data packet protocol session; sending a second SIP
registration request comprising the unique device identifier
appended to another of the plurality of registration extensions;
and utilizing a second data packet protocol session in response to
an access network detecting the unique device identifier,
authenticating that the unique device identifier is a subscriber,
and responding with a second network address to enable the second
data packet protocol session.
14. The method of claim 13, wherein sending the first and second
SIP registration requests further comprising establishing multiple
session through a single SIP proxy server.
15. The method of claim 13, further comprising: establishing the
first SIP registration with a first access network; and
establishing the second SIP registration with a second access
network.
16. The method of claim 15, further comprising: accessing a
preference for receiving a communication service from the second
access network; establishing the first SIP registration with the
first access network in response to the second access network being
unavailable; and establishing the second SIP registration with the
second access network when available while maintaining session
continuity.
17. The method of claim 15, further comprising: establishing the
first SIP registration with the first access network to receive a
communication service when the first access network is available;
establishing the second SIP registration with the second access
network when available to receive the communication service when
the second access network is available; and maintaining
communication service continuity by selectively switching between
the two active SIP registrations.
18. The method of claim 15, further comprising: establishing the
first SIP registration to a cellular circuit switch; and
establishing the second SIP registration to a wireless local access
network.
19. The method of claim 13, further comprising: sending to a first
SIP proxy server a first multiple registration request containing
the unique device identifier for being forwarded to an SIP
registrar server that detects the unique device identifier.
20. The method of claim 19, further comprising: sending a second
multiple registration request to a second SIP proxy server;
receiving a failure message from the second SIP proxy server;
sending the second SIP registration request to the second SIP proxy
server comprising the unique device identifier appended to another
of the plurality of registration extensions to the second SIP proxy
server for forwarding to the SIP registrar server that detects the
unique device identifier and multiple registration.
21. At least one processor configured to initiate multiple session
registrations of a data packet protocol for a user equipment
assigned a unique device identifier, comprising: a first module for
sending a first session initiation protocol (SIP) registration
request comprising a unique device identifier for the user
equipment appended to one of a plurality of registration
extensions; a second module for utilizing a first data packet
protocol session in response to an access network detecting the
unique device identifier, authenticating that the unique device
identifier is a subscriber, and responding with a network address
to enable the first data packet protocol session; a third module
for sending a second SIP registration request comprising the unique
device identifier appended to another of the plurality of
registration extensions; and a fourth module for utilizing a second
data packet protocol session in response to an access network
detecting the unique device identifier, authenticating that the
unique device identifier is a subscriber, and responding with a
second network address to enable the second data packet protocol
session.
22. A computer program product, comprising: a computer-readable
medium comprising: a first set of codes for causing a computer to
send a first session initiation protocol (SIP) registration request
comprising a unique device identifier for the user equipment
appended to one of a plurality of registration extensions; a second
set of codes for causing the computer to utilize a first data
packet protocol session in response to an access network detecting
the unique device identifier, authenticating that the unique device
identifier is a subscriber, and responding with a network address
to enable the first data packet protocol session; a third set of
codes for causing the computer to send a second SIP registration
request comprising the unique device identifier appended to another
of the plurality of registration extensions; and a fourth set of
codes for causing the computer to utilize a second data packet
protocol session in response to an access network detecting the
unique device identifier, authenticating that the unique device
identifier is a subscriber, and responding with a second network
address to enable the second data packet protocol session.
23. An apparatus for supporting multiple session registrations of a
data packet protocol, comprising: means for sending a first session
initiation protocol (SIP) registration request comprising a unique
device identifier for the user equipment appended to one of a
plurality of registration extensions; means for utilizing a first
data packet protocol session in response to an access network
detecting the unique device identifier, authenticating that the
unique device identifier is a subscriber, and responding with a
network address to enable the first data packet protocol session;
means for sending a second SIP registration request comprising the
unique device identifier appended to another of the plurality of
registration extensions; and means for utilizing a second data
packet protocol session in response to an access network detecting
the unique device identifier, authenticating that the unique device
identifier is a subscriber, and responding with a second network
address to enable the second data packet protocol session.
24. An apparatus for supporting multiple session registrations of a
data packet protocol, comprising: a transmitter for sending first
and second session initiation protocol (SIP) registration requests
comprising a unique device identifier for the user equipment
appended to one of a plurality of registration extensions; a
processor for utilizing first and second data packet protocol
sessions in response to at least one access network detecting the
unique device identifier, authenticating that the unique device
identifier is a subscriber, and responding with a network address
for each SIP registration request to enable the first and second
data packet protocol sessions.
Description
BACKGROUND
[0001] This invention relates to session continuity for data packet
wireless communication between networks using different
communication standards.
[0002] Wireless communication proliferates with introductions of
new transmission modes, communication protocols, and types of
communication content. Examples of wireless communication systems
include the public land mobile network (PLMN) and the wireless
local area network (WLAN). In order for a mobile station, also
referred to as user equipment (UE), to have access to a
communication channel at various locations, increasingly a
multi-access or multi-mode capability is incorporated into a single
handheld UE. In addition, more functionality is being incorporated,
including voice and data services. This integration poses
challenges for seamless multi-access and session continuity as the
UE moves within range of various access networks. The interworking
between Third Generation Partnership Project (3GPP) (e.g., Global
System for Mobile Communications/General Packet Radio Service
(GSM/GPRS), Wideband Code Division Multiple Access (WCDMA), High
Speed Downlink Packet Access (HSDPA)) and other access technologies
such as IEEE 802.11 (WiFi), for instance, creates situations where
interruptions in service or inability to multi-access are
likely.
[0003] Multi-access refers to the ability to use multiple different
access networks with a single communications device. The
communications device may, for example, be connected to the
Internet at first using a WLAN and, when outside the coverage of
the WLAN network, using conventional circuit switch (CS)
communications network.
[0004] Session continuity refers to maintaining upper level
connections, for example transport level connection for a data
packet protocol communication, when the access technology, that is
the link layer, changes. This means, for example, that applications
in a communications device or user of a communication device does
not notice changes in access technology or interruptions in
connectivity.
[0005] Examples of access technologies and communication services
include traditional CS services (i.e., voice/Short Message Service
(SMS)) along with some packet data service (e.g., presence and
instant messaging) over GSM and Universal Mobile Telecommunication
System (UMTS) access. Voice Over IP (VoIP), SMS-IP, and other
packet data services (e.g., push-to-talk, video sharing, etc.) are
available over Wireless Fidelity (WiFi) as well as UMTS/HSDPA. Some
services, such as broadcast/multicast, are available over UMTS but
not HSDPA/WiFi.
[0006] Considerable deployment of wireless infrastructure and UEs
have been made utilizing IMS (IP Multimedia Subsystem), which is an
internationally recognized standard that specifies interoperability
and roaming between devices and provides bearer network control and
security. It is also well integrated with existing voice and data
networks, and hence makes IMS an important enabling technology for
fixed-mobile devices. IMS also makes efficient use of existing
circuit- and packet-switched technologies. The third generation
(3G) IMS comprises a core network subsystem within the Universal
Mobile Telecommunication System (UMTS), which uses the Session
Initiation Protocol (SIP) to initiate, modify and terminate
multimedia sessions. IMS also uses the IETF Session Description
Protocol (SDP) to define session parameters, as well as negotiate
codecs to be used during the multimedia session.
[0007] The IMS architecture requires that each UE register the
network address provided by the access network by sending a unique
device identifier that is authenticated by a home service provider.
The problem thus is that a UE cannot maintain simultaneous
registrations via different access technologies, such as WLAN,
UMTS, 1x Evolution-Data Optimized (EV-DO), etc. Thus, it is not
possible to maintain session continuity, to deliver services over a
preferred access, or to have simultaneous services over different
accesses.
[0008] With regard to the first scenario of maintaining session
continuity over multiple access technologies, considerable
development has addressed certain aspects of the problem. Mobile IP
protocol takes care that data packets relating to a communication
device's home IP address are routed from a home network to a
care-of address at a mobile location of the communication device.
While this allows certain simultaneous registration, the Mobile IP
provisioning functionality at the network end imposes certain
challenges for implementation. In addition, the Mobile IP protocol
entails extra headers relating to tunneling to be present in data
packets. Given the limited throughput typical of wireless access
networks, this overhead tends to degrade the data transfer
capabilities to utilize Mobile IP.
[0009] It has also been proposed that changes be made to the IMS
architecture so that at the point where the communication converges
from two access networks. The unique device identifier would be
detected with the two different network addresses with some
provisions made to allow simultaneous registrations when desired
and to override a prior registration in other situations. However,
such an implementation assumes that the two communication channels
would have network addresses assigned by different proxy call
session control function (P-CSCF), which is not necessarily the
case.
[0010] With regard to the second scenario of automatically
switching to a preferred access network, it is possible that a UE
is within the coverage of multiple access networks (e.g., UMTS and
WiFi). A user of the UE may prefer to receive a service (e.g.,
push-to-talk) over a particular access network (e.g., UMTS).
However, this would require the UE to be registered in the IMS
domain over both WiFi and UTMS access networks, which is
prevented.
[0011] With regard to the third scenario of simultaneous services,
it may be desirable for the UE to receive different services over
multiple accesses simultaneously (e.g., video streaming over WiFi
and push-to-talk over UMTS).
SUMMARY
[0012] The following presents a simplified summary in order to
provide a basic understanding of some aspects of the disclosed
versions. This summary is not an extensive overview and is intended
to neither identify key or critical elements nor delineate the
scope of such versions. Its purpose is to present some concepts of
the described versions in a simplified form as a prelude to the
more detailed description that is presented later.
[0013] A user equipment registers selectively to more than one IMS
(IP Multimedia Subsystem) capable access network by emulating more
than one unique device identifier in a session initiation protocol
(SIP) registration request so that a new IMS registration does not
necessarily cause the overwriting of an assigned network address to
correspond to the new access network. The SIP registrar server or
home subscriber server is still able to discern the unique device
identifier within the registration information and enables the
multiple sessions. Thereby, uses are supported whereby the user
equipment seeks to enhance session continuity, seeks to utilize
preferred access networks when coverage exists for multiple access
networks, or wants to utilize multiple access networks
simultaneously.
[0014] In one aspect, a method for supporting multiple session
registrations of a data packet protocol for a user equipment
assigned a unique device identifier is by receiving a plurality of
registration requests from a user equipment. Each registration
request appears unique in that the unique device identifier is
appended to one of a plurality of registration extensions so that
the access network(s) do not necessarily drop an earlier session
from the same user equipment. Yet, a downstream enabler of the
multiple sessions is still capable of detecting the unique device
identifier, authenticating that the unique device identifier is a
subscriber, and allowing the multiple data packet sessions.
[0015] In an additional aspect, at least one processor is
configured to support multiple session registrations of a data
packet protocol for a user equipment assigned a unique device
identifier by having modules for receiving a plurality of
registration requests from a user equipment. Each registration
request appears unique in that the unique device identifier is
appended to one of a plurality of registration extensions so that
the access network(s) do not necessarily drop an earlier session
from the same user equipment. Yet, a downstream enabler of the
multiple sessions is still capable of detecting the unique device
identifier, authenticating that the unique device identifier is a
subscriber, and allowing the multiple data packet sessions.
[0016] In yet an additional aspect, a computer program product has
a computer-readable medium containing sets of codes for causing a
computer to support multiple session registrations of a data packet
protocol for a user equipment assigned a unique device identifier
is by receiving a plurality of registration requests from a user
equipment. Each registration request appears unique in that the
unique device identifier is appended to one of a plurality of
registration extensions so that the access network(s) do not
necessarily drop an earlier session from the same user equipment.
Yet, a downstream enabler of the multiple sessions is still capable
of detecting the unique device identifier, authenticating that the
unique device identifier is a subscriber, and allowing the multiple
data packet sessions.
[0017] In another aspect, an apparatus for supporting multiple SIP
registrations is given that has a means for receiving a first SIP
registration request from a user equipment comprising a unique
device identifier for the user equipment appended to one of a
plurality of registration extensions. A means is provided for
detecting the unique device identifier, authenticating that the
unique device identifier is a subscriber, and responding with a
network address to enable a first data packet protocol session. In
addition, a means is provided for receiving a second SIP
registration request from the user equipment comprising the unique
device identifier appended to another of the plurality of
registration extension, for detecting the unique device identifier,
authenticating that the unique device identifier is a subscriber,
and responding with a second network address to enable a second
data packet protocol session.
[0018] In yet another aspect, an apparatus for supporting multiple
session registrations of a data packet protocol includes user
equipment having memory that contains a unique device identifier. A
processor generates SIP registration requests comprising the unique
device identifier appended to one of a plurality of registration
extensions and for generating a second SIP registration comprising
the unique device identifier appended to another of the plurality
of registration extensions. At least one transceiver sends the SIP
registration requests to at least one SIP proxy server and receives
corresponding network addresses to establish multiple data packet
protocol sessions. An SIP registrar server includes a memory
containing a subscriber database containing the unique device
identifier and a temporary network address data structure. A
processor detects the unique device identifier and the network
addresses in communications from the at least one SIP proxy. By
authenticating the unique device identifier and by recognizing the
multiple sessions, the processor enables multiple simultaneous
registrations for the user equipment.
[0019] In another aspect, a method for initiating multiple session
registrations of a data packet protocol for a user equipment
assigned a unique device identifier utilizes the method of sending
first and second SIP registration requests, each made to appear
unique by appending an extension to the unique device identifier
and then utilizing two data packet protocol sessions established by
the two requests.
[0020] In yet another aspect, at least one processor for initiating
multiple session registrations of a data packet protocol for a user
equipment assigned a unique device identifier comprises modules for
sending first and second SIP registration requests, each made to
appear unique by appending an extension to the unique device
identifier and then utilizing two data packet protocol sessions
established by the two requests.
[0021] In yet a further aspect, a computer program product has a
computer-readable medium containing sets of codes for sending first
and second SIP registration requests, each made to appear unique by
appending an extension to the unique device identifier and then
utilizing two data packet protocol sessions established by the two
requests.
[0022] In an additional aspect, an apparatus is given for
requesting multiple session registrations of a data packet protocol
first uses means for sending first and second SIP registration
requests, each made to appear unique by appending an extension to
the unique device identifier and then a means for utilizing two
data packet protocol sessions established by the two requests.
[0023] In yet another aspect, an apparatus for requesting multiple
session registrations of a data packet protocol includes a
transmitter for sending first and second session initiation
protocol (SIP) registration requests of a unique device identifier
for the user equipment appended to one of a plurality of
registration extensions. The apparatus also includes a processor
for utilizing first and second data packet protocol sessions in
response to at least one access network detecting the unique device
identifier, authenticating that the unique device identifier is a
subscriber, and responding with a network address for each SIP
registration request to enable the first and second data packet
protocol sessions.
[0024] To the accomplishment of the foregoing and related ends, one
or more versions comprise the features hereinafter fully described
and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative aspects and are indicative of but a few of the various
ways in which the principles of the versions may be employed. Other
advantages and novel features will become apparent from the
following detailed description when considered in conjunction with
the drawings and the disclosed versions are intended to include all
such aspects and their equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a diagram of a communication system wherein a user
equipment may make registrations to two access networks.
[0026] FIG. 2 is a schematic diagram of one aspect of components of
the user equipment of the communication system of FIG. 1.
[0027] FIG. 3 is a block diagram of an Internet Protocol Multimedia
Subsystem (IMS) communication system including a UTMS data packet
access network and a Wireless Local Access Network (WLAN) in
communication with a user equipment.
[0028] FIG. 4 is a data structure diagram for an extended unique
device identifier utilized by the user equipment of FIG. 3.
[0029] FIG. 5 is a message flow diagram of use of different
registration identifications by a user equipment implying
simultaneous registration.
[0030] FIG. 6 is a message flow diagram of use of the same
registration identification by a user equipment implying overriding
registration.
[0031] FIG. 7 is a message flow diagram of change in Serving-Call
Session Control Function (C-CSCF) behavior to support simultaneous
registrations.
[0032] FIG. 8 is a message flow diagram of simultaneous
registration support in Proxy-Call Session Control Function
(P-CSCF).
DETAILED DESCRIPTION
[0033] A mobile communication system that utilizes multiple access
technologies achieves multiple session registrations by deriving a
plurality of extended unique device identifications from a specific
unique device identification assigned to a user equipment. Each of
the plurality of extended unique device identifications have the
benefit of allowing multiple registrations with one or more access
networks while allowing a home subscriber system to detect the one
unique device identification embedded in the extended unique device
identifications for authentication purposes. Thereby, a large
population of deployed UEs and access network infrastructure may
benefit without replacement by allowing a UE to maintain session
continuity when transitioning between access networks, to select a
preferred access technology when in overlapping coverage areas
without session interruption, or to maintain multiple sessions
(e.g., simultaneous Voice over IP (VoIP) and media streaming) with
different access networks.
[0034] Various aspects are now described with reference to the
drawings. In the following description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of one or more aspects. It may be
evident, however, that the various aspects may be practiced without
these specific details. In other instances, well-known structures
and devices are shown in block diagram form in order to concisely
describing these versions.
[0035] With reference to FIG. 1, a communication system 10 enables
a user equipment (UE) 12 to wirelessly communicate to at least two
different access networks 14, 16 utilizing Mode A and B transceiver
circuitry 18, 20, respectively. In particular, the UE 12 can start
a session, depicted at 22, advantageously registering an extended
unique device identifier (EUDID) A that includes a unique device
identifier 24 stored on the UE 12. An address registering server A
26 of the access network 14 assigns a network address A to the UE
12 in order to establish the session and passes this information to
a gateway 28 to a data packet network 30. A home subscriber server
32 detects the unique device ID 24 within the EUDID and
authenticates this unique device ID 24 in a subscriber database 34
and stores the temporary network related information 36.
[0036] It should be appreciated with the benefit of the present
disclosure that a multiple link function 40 incorporated into the
UE 12 that embeds the unique device ID 24 into the EUDID has an
advantage of providing a large if not unlimited number of
variations for multiple registrations. The address registering
server 26 of the access network A 14 would accept as a different
registration each of the variations of the unique device ID 24
represented by the EUDID, yet the home subscriber server 32 can
recognize the multiple registrations during authentication of each
session. Moreover, already deployed UEs 12 having unique device IDs
24 already assigned may benefit from utilizing this approach
without necessitating replacement and large-scale infrastructure
modifications.
[0037] Thereafter, one of three situations occurs requiring an
additional registration to an access network 14, 16. The first is
when the UE 12 moves from the coverage area of access network A 14
to the coverage area of access network B 16 during a session
registered with EUDID A and network address A. The multiple link
function 40 of the UE 12 derives another EUDID B from the unique
device ID 24 and transmits it as depicted at 42 from mode B
transceiver circuitry 20 to an address registering server B 44. The
address registering server B 44 of the access network B 14 assigns
a network address B to the UE 12 in order to establish a session
and passes this information to a gateway 46 to the data packet
network 30. The home subscriber server 32 detects the unique device
ID 24 within the EUDID B and authenticates this unique device ID 24
in the subscriber database 34 and stores the temporary network
related information 36. Thereafter, the multiple link function 40
may maintain a seamless user experience during a transition when
receiving over one or both of the two network addresses A, B to
maintain session continuity.
[0038] In a second situation, the multiple link function 40
advantageously recognizes that the UE 12 is simultaneously within
the coverage area of the two access networks 14, 16 and that a
current session is not registered with the preferred access
network. Thus, the multiple link function 40 initiates the second
registration as previously described.
[0039] In a third situation, the multiple link function 40 of the
UE 12 seeks to initiate multiple registrations with the same
address registering server A 26, as depicted at 48. Use of a
different EUDID allows the address registering server A 26 to
register the UE 12 a second time, which would have been precluded
if the same code had been used.
[0040] With reference to FIG. 2, according to some aspects, the UE
12 may comprise any type of computerized, communication device. For
example, as illustrated in FIG. 2, the UE 12 may comprise a mobile
communication device, such as a wireless and/or cellular telephone.
Alternatively, the UE 12 may comprise a fixed communication device,
such as a Proxy Call/Session Control Function (P-CSCF) server, a
network device, a server, a computer workstation, etc. It should be
understood that UE 12 is not limited to such a described or
illustrated device, but may further include a Personal Digital
Assistant (PDA), a two-way text pager, a portable computer having a
wired or wireless communication portal, and any type of computer
platform having a wired and/or wireless communications portal.
Further, the UE 12 can be a remote-slave or other similar device,
such as remote sensors, remote servers, diagnostic tools, data
relays, and the like, which does not have an end-user thereof, but
which simply communicates data across a wireless or wired network.
In alternate aspects, the UE 12 may be a wired communication
device, such as a landline telephone, personal computer, set-top
box or the like. Additionally, it should be noted that any
combination of any number of UEs 12 of a single type or a plurality
of the afore-mentioned types may be utilized in the communication
system 10. Therefore, the present apparatus and methods can
accordingly be performed on any form of wired or wireless device or
computer module, including a wired or wireless communication
portal, including without limitation, wireless modems, Personal
Computer Memory Card International Association (PCMCIA) cards,
access terminals, personal computers, telephones, or any
combination or sub-combination thereof.
[0041] Additionally, the UE 12 may include a user interface 50 for
purposes such as requesting, interacting with, and/or playing
multimedia content, performing voice or data communication, etc.
This user interface 50 includes an input device 52 operable to
generate or receive an input into the UE 12, and an output device
54 operable to generate and/or present information for consumption
by the user of the UE 12. For example, input device 52 may include
at least one device such as a keypad and/or keyboard, a mouse, a
touch-screen display, a microphone in association with a voice
recognition module, etc. In certain aspects, input device 52 may
provide for user input of a request for content or for user input
of a request for additional information. Further, for example,
output device 54 may include a display, an audio speaker, a haptic
feedback mechanism, etc. Output device 54 may generate a graphical
user interface, a sound, a feeling such as a vibration, etc.
[0042] Further, UE 12 may include a computer platform 56 operable
to execute applications to provide functionality to the device, and
which may further interact with input device 52 and output device
54. Computer platform 56 may include a memory 58, which may
comprise volatile and nonvolatile memory portions, such as
read-only and/or random-access memory (RAM and ROM), erasable
programmable read-only memory (EPROM), electrically erasable
programmable read-only memory (EEPROM), flash memory, and/or any
memory common to computer platforms. Further, memory 58 may include
active memory and storage memory, including an electronic file
system and any secondary and/or tertiary storage device, such as
magnetic media, optical media, tape, soft and/or hard disk, and
removable memory components.
[0043] Further, computer platform 56 may also include a processor
59, which may be an application-specific integrated circuit (ASIC),
or other chipset, processor, logic circuit, or other data
processing device. In some aspects, such as when UE 12 comprises a
cellular telephone, processor 59 or other logic such as ASIC may
execute an application programming interface (API) layer 60 that
interfaces with any resident software components, such as voice
call, data call, and media-related applications in memory 58. API
60 may be a runtime environment executing on the respective
communication device. One such runtime environment is Binary
Runtime Environment for Wireless.RTM. (BREW.RTM.) software
developed by Qualcomm Incorporated of San Diego, Calif. Other
runtime environments may be utilized that, for example, operate to
control the execution of applications on wireless computing
devices.
[0044] Additionally, processor 59 may include various processing
subsystems 62 embodied in hardware, firmware, software, and
combinations thereof, that enable the functionality of UE 12 and
the operability of the UE 12 on communication system 10 (FIG. 1).
For example, processing subsystems 62 allow for initiating and
maintaining communications, and exchanging data, with other
networked devices as well as within and/or among components of UE
12. In one aspect, such as in a cellular telephone, processor 59
may include one or a combination of processing subsystems 62, such
as: sound, non-volatile memory, file system, transmit, receive,
searcher, layer 1, layer 2, layer 3, main control, remote
procedure, handset, power management, diagnostic, digital signal
processor, vocoder, messaging, call manager, Bluetooth.RTM. system,
Bluetooth.RTM. LPOS, position determination, position engine, user
interface, sleep, data services, security, authentication, USIM/SIM
(universal subscriber identity module/subscriber identity module),
voice services, graphics, USB (universal serial bus), multimedia
such as MPEG (Moving Picture Experts Group) protocol multimedia,
GPRS (General Packet Radio Service), short message service (SMS),
short voice service (SVS.TM.), web browser, etc. For the disclosed
aspects, processing subsystems 62 of processor 59 may include any
subsystem components that interact with applications executing on
computer platform 56. GPRS is a packet data communications system
integrated with the GSM cellular telephone system.
[0045] Computer platform 56 may further include communication
modules 64 that enables communications among the various components
of UE 12, as well as being operable to exchange data and
communication requests between the UE 12 and the communication
system 10 (FIG. 1). Communication modules 64 may be embodied in
hardware, firmware, software and/or combinations thereof, and may
further include all protocols for use in intra-device and
inter-device communications. Further, communication modules 64 are
operable to transmit and/or receive information, in accordance with
the apparatus and methods described herein.
[0046] The multiple link function 40 resident in memory 58 can
utilize the communication modules 64 to initiate and maintain two
separate network registrations, based upon extended unique device
identification (EUDID) data structure 70 maintained in memory 58 so
that a channel A application 72 and a channel B application 74 may
execute in memory 66. In particular, the multiple link function 70
may maintain session continuity during a transition between channel
applications 72, 74, may select a preferred channel application 72,
74, or maintain simultaneous channel applications 72, 74.
[0047] In some aspects, the memory 58 of the UE 12 may further
store a user interface module 76 to operate the user interface 50,
such as for retrieving, storing and playing multimedia content in a
background or a foreground process or effecting a communication
session. The user interface module 76 may comprise one or any
combination of hardware, software, firmware, data and executable
instructions operable to perform these functions, including a media
player appropriate for the type of multimedia content and
capabilities of the user interface 50.
[0048] The UE 12 can have multiple mode capability utilized by the
communication module 64 by including Mode A transmit and receive
circuitry 78, 80 (e.g., CS link) and Mode B transmit and receive
circuitry 82, 84 (e.g., WiFi link).
[0049] In the illustrative UE 12 of FIG. 2, the computer platform
56 is provisioned for session initiation protocol (SIP) by
including a subscriber identity module (SIM) 90 that may be
compatible with, or encompass, one or more of a standard SIM,
universal subscriber identity module (USIM), and an IMS subscriber
identity module (ISIM).
[0050] In the exemplary version, the SIM 90 is a UICC (UMTS
Integrated Circuit Card), which is the chip card used in mobile
terminals in GSM and UMTS networks. The UICC ensures the integrity
and security of all kinds of personal data. In a GSM network, the
UICC contains a SIM application and in a UMTS network it is the
USIM application. A UICC may contain several applications 92,
making it possible for the same smartcard to give access to both
GSM and UMTS networks, and also provide storage of a phone book and
other applications. In support of UMTS release 5, the IP multimedia
Services Identity Module (ISIM) is required for services in the
IMS. IP Multimedia Services Identity Module (ISIM) is an
application running on a UICC smart card in a 3G mobile telephone
in the IP Multimedia Subsystem (IMS). It contains parameters for
identifying and authenticating the user to the IMS. The ISIM
application can co-exist with SIM and USIM on the same UICC making
it possible to use the same smartcard in both GSM networks and
earlier releases of UMTS.
[0051] The ISIM 90 consists of a SIM processor (CPU) 94, read only
memory (ROM) 96, random access memory (RAM) 98, nonvolatile memory
(e.g., EEPROM) 100 and input/output (I/O) circuitry 102. The ROM 96
contains a SIM operating system 104, the SIM applications 92, and
security algorithms A3, A8 106. The RAM 98 is used for buffering
transmission data and executing the applications 92, 106. The
EEPROM 100 contains the unique device identification (UDID).
[0052] In the illustrative version, this unique device
identification is derived from those codes stored in accordance
with the SIM and ISIM standards. The SIM standard employs the
following codes: International Mobile Subscriber Identity (IMSI),
Temporary Mobile Subscriber Identity (TMSI), International Mobile
Equipment Identity (IMEI), and Mobile Subscriber ISDN Number
(MSISDN). The IMSI is a unique user identity that is stored in the
SIM. To improve privacy, a TMSI is generated per geographical
location. While IMSI/TMSI are used for user identification, the
IMEI is a unique device identity and is phone specific. The MSISDN
is the telephone number of a user. With IMS, the following
additional identities are implemented: IP Multimedia Private
Identity (IMPI) and IP Multimedia Public Identity (IMPU). To that
end, the EEPROM 100 stores a Subscriber ID (IMSI, Pin) 108, a call
number (IMSI, MSISDN) 110, equipment ID (IMEI) 112, keys Ki 114,
and network-related information (TMSI, LAI) 118. LAI (Location Area
Identity) identifies under which Base Station Controller the UE 12
is currently present. The EEPROM 100 also contains the private user
identification (PIID) 120 and the public user identification (PUID)
122.
[0053] The use and content of the ISIM 90 can be protected by use
of PIN codes (not depicted). One code, PIN1, can be defined to
control normal use of the phone. Another code, PIN2, can be set, to
allow the use of special functions (like limiting outbound
telephone calls to a list of numbers). PUK1 and PUK2 (i.e., pin
unlock key 1, 2) is used to reset PIN1 and PIN2 respectively.
[0054] With the ISIM 90 thus provisioned, the UE 12 may utilize
Session Initiation Protocol (SIP), which is the protocol used for
call control in the third generation mobile network starting from
the 3GPP release 5. SIP uses textual encoding, which makes it
easier to build services based on SIP, design extensions to SIP and
debug the protocol. SIP is specified by the Internet Engineering
Task Force (IETF) and comprises a highly generalized and widely
applicable protocol for establishing user sessions across packet
networks. SIP affords the capability for users to establish
sessions that can transfer multimedia data, including for example
voice, video, and audio, between two or more participants. The
session is established according to a specified protocol including
"invite" messages issued from a client requesting access to an
asset on another device ("server").
[0055] At the most general level, SIP sessions utilize up to four
major components: (i) SIP User Agents (UA) which are the UEs 12,
such as cell phones, multimedia handsets, personal computers (PCs),
personal digital assistants (PDAs), etc. used to create and manage
a SIP session; (ii) SIP Registrar Servers, which are databases that
contain the location of all User Agents within a particular domain;
in SIP messaging, these servers retrieve and send participants' IP
addresses and other pertinent information to the SIP Proxy Server;
(iii) SIP Proxy Servers accept session requests made by a SIP UA
and query the SIP Registrar Server to obtain the recipient UAs
addressing information; the session invitation is then forwarded
directly to the recipient UA if it is located in the same domain or
to a Proxy Server if the UA resides in another domain; and (iv) SIP
Redirect Servers which allow SIP Proxy Servers to direct SIP
session invitations to external domains. SIP Redirect Servers may
reside in the same hardware as SIP Registrar Servers and SIP Proxy
Servers. Together, these systems deliver messages embedded with the
SDP protocol defining their content and characteristics to complete
a SIP session.
[0056] IMS (IP Multimedia Subsystem) is an internationally
recognized standard that specifies interoperability and roaming
between devices and provides bearer network control and security.
It is also well integrated with existing voice and data networks,
and hence makes IMS an important enabling technology for
fixed-mobile devices. IMS also makes efficient use of existing
circuit- and packet-switched technologies. The 3G IMS comprises a
core network subsystem within the Universal Mobile
Telecommunication System (UMTS), which uses the Session Initiation
Protocol (SIP) to initiate, modify and terminate multimedia
sessions. IMS also uses the IETF Session Description Protocol (SDP)
to define session parameters, as well as negotiate codecs to be
used during the multimedia session.
[0057] SIP runs atop different transport protocols such as the User
Datagram Protocol (UDP) and the Transmission Control Protocol
(TCP), and hence typically is implemented at the Session Layer. The
IMS architecture (specified in 3GPP TS 23.22829) is built upon the
UMTS packet domain. However, the IMS architecture is purposely
designed so as to be forward-compatible with mechanisms for IP
connectivity other than those utilized by the UMTS packet domain.
This feature is known as "access network independence", and affords
a significant degree of flexibility and forward compatibility. For
example, in the context of security, the generalized IETF
architecture of SIP allows several security/trust models to be
defined, providing hop-by-hop, end-to-middle and end-to-end
security solutions. The IETF SIP working group has accordingly
defined several security mechanisms that can be applied to the
different uses of SIP. These mechanisms offer, for example,
authentication, message integrity, confidentiality, and replay
protection. A 3GPP IMS subscriber has one IP multimedia private
identity (IMPI) and at least one IP multimedia public identity
(IMPU). To participate in multimedia sessions, an IMS subscriber
must register at least one IMPU with the IMS. The private identity
is generally used only for authentication purposes.
[0058] With reference to FIG. 3, a dual mode communication system
210 is depicted as including a dual-mode mobile station 212 having
a channel A wireless communication path to an IP-connectivity
Access Network (IP CAN) A, connecting an IMS subscriber to IMS
services, depicted as UMTS packet data network 214. Typically the
IP CAN will be General Packet Radio Service (GPRS) either being
supported by GSM EDGE Radio Access Network (GERAN) 215 or UMTS
Terrestrial Radio Access Network (UTRAN) 217 functionality. The
dual-mode mobile station 212 also has a channel B wireless
communication path to an access network B 216, depicted as a WiFi
access network 218 and an IP CAN 220 comprising a Packet Data
Gateway (PDG) 223 communicating to a Wireless Access Gateway (WAG)
225 which is in SIP/IETF Realtime Transport Protocol (RTP)
communication with a WiFi access point (AP) 227.
[0059] There are several IMS "entities" that are generally relevant
to the 3G IMS architecture. The UE 12 contains the SIP user agent
(UA) and the ISIM 90 that contains the IMS security information. As
described, the ISIM 90 can be a distinct application sharing no
data and functions with the USIM, or it can share data and security
functions with the USIM or it can be a reused USIM. There can only
be one ISIM 90 per IMPI. A proxy call session control function.
(P-CSCF) acts as an outbound SIP proxy. The P-CSCF is the first
contact point in the serving network and forwards SIP requests
towards an interrogating call session control function (I-CSCF).
The I-CSCF is the contact point in the home network and acts as a
SIP proxy. It forwards SIP requests or responses towards a serving
call session control function and may be located at any number of
different locations. The Serving-Call Session Control Function
(S-CSCF) may behave as a SIP registrar, a SIP proxy server and a
SIP UA. Before the UE can send a SIP INVITE message to invoke a
session, it must first register an IMPU with the S-CSCF. The
registration of an IMPU is accomplished by the UE by sending a SIP
REGISTER message towards the home network.
[0060] Sessions are established using INVITE messages. In one
scenario, an INVITE message is sent from one UE to another, both of
which reside in a 3GPP network. The INVITE from UE in the first
Home Network first passes through a P-CSCF and then to an I-CSCF,
which forwards the message to a home subscriber system (HSS) 230,
which looks up to which S-CSCF the user is registered. A similar
process is performed within the second Home Network, and the INVITE
message is terminated, for example in another UE for a voice
communication. The IMS transmission may now start, for example, by
using the IETF Realtime Transport Protocol (RTP).
[0061] Returning to FIG. 3, the GERAN 215 communicates via Iu
interface and the UTRAN 217 communicates via a IU/Gb interface to a
Serving GPRS Support Node/Gateway GPRS Support Node (SGSN/GGSN)
231, which in turn is in communication via a Gs interface to a
Visitor Location Register (VLR) 233, via a Gr/Gc interface to the
HSS 230, and via a Gr/Gc interface to a Home Location
Register/Authentication Center (HLR/AuC) 235. VLR 233 contains
selected administrative information from the HLR 235, necessary for
call control and provision of the subscribed services, for each
mobile currently located in the geographical area controlled by the
VLR 233.
[0062] Although each functional entity can be implemented as an
independent unit, most manufacturers of switching equipment
implement one VLR together with one Mobile services Switching
Center (MSC), so that the geographical area controlled by the MSC
corresponds to that controlled by the VLR. The MSC acts like a
normal switching node of the PSTN or ISDN, and in addition provides
all the functionality needed to handle a mobile subscriber, such as
registration, authentication, location updating, handovers, and
call routing to a roaming subscriber. These services are provided
in conjunction with several functional entities, which together
form the Network Subsystem. The MSC provides the connection to the
public fixed network (PSTN or ISDN), and signaling between
functional entities. The Home Location Register (HLR) provides the
Call routing and (possibly international) roaming capabilities of
GSM. The HLR contains all the administrative information of each
subscriber registered in the corresponding GSM network, along with
the current location of the mobile. There is logically one HLR per
GSM network, but it may be implemented as a distributed database.
The HLR stores all permanent subscriber data and the relevant
temporary data of all subscribers permanently registered in the
HLR. The IMSI (International Mobile Subscriber Identity) and
authentication data are stored in it. The Authentication Center
(AuC) is a protected database that stores a copy of the secret key
stored in each subscriber's SIM card, which is used for
authentication and ciphering of the radio channel. The Visitor
Location Register (VLR) 233 is a database--part of the GSM mobile
phone system--which stores information about all the mobile
stations that are currently under the jurisdiction of the MSC
(Mobile Switching Center) which it serves. Of all the information
it stores about each MS (Mobile Station), the most important is the
current LAI (Location Area Identity). LAI identifies under which
BSC (Base Station Controller) the MS is currently present. This
information is vital in the call setup process. Whenever an MSC
detects a new MS in its network, in addition to creating a new
record in the VLR, it also updates the HLR of the mobile subscriber
with the new location of that MS.
[0063] IMS domain 250 supports both access networks 214, 216 and
includes the HSS 230. In particular, a call state control function
(CSCF) 252 communicates with the HSS 230 via a Sh interface,
communicates with the SGSN/GGSN 231 via an interface Gi/Gp,
communicates via SIP signaling to the PDG 223, and via SIP
signaling with Media Gateway Control Function (MGCF) 254, which in
turn communicates via Media Gateway Control (IETF working group)
(MEGACO) to media gateway (MGW) 256, which in turn communicates via
RTP to the PDG 223.
[0064] FIG. 3 is annotated to denote simultaneous or sequential
registration with mobile station 212 IMS registered over channel A
at IP address 1, Public ID 1 (puid1) (p-access-info: access-id-1
and with mobile station 212 IMS registered over channel B at IP
address 2, Public ID 1 (puid1) (p-access-info: access-id-2).
[0065] In FIG. 4, an exemplary version of the extended unique
device identifier (EUDID) 70, which is one of many that can be
derived from the one unique device identifier (e.g., PIID 120),
begins with a unique identifier field 300 (e.g., the PIID 120). An
extension field 302 can be appended to the unique identifier field
300. For instance, the extension field 302 can include three
base-10 digits that will allow the UE 12 to have 1000 concurrent
links. This approach allows passing through a conventional P-CSCF
that would otherwise not allow multiple registrations. The EUDID 70
may advantageously include an identification field 304 that
communicates an intention for multiple registrations for those
P-CSCF capable of interpreting this information.
[0066] Thus, this EUDID 70 can be used to register without
modifications to the P-CSCF by having the UE and S-CSCF emulate
different IMPIs using the IMPI that is assigned to the device. As
an example, UE-A is assigned IMPI=privateIDA@networkdomain.com.
When registering with IP-address-1 via IP-CAN1, UE-A adds a suffix
to the IMPI such as IMPI_ext1=privateIDA_ext1@networkdomain.com.
When registering with IP-address-2 via IP-CAN2, UE-A adds a suffix
to the IMPI such as IMPI_ext2=privateIDA_ext2@networkdomain.com.
This allows the UE-A to send two REGISTER requests with different
IMPIs from point of view of the P-CSCF. However, the S-CSCF
recognizes the extensions to the IMPI and removes the extension
before querying the HSS etc. Thus, this solution only requires an
upgrade in the UE and S-CSCF behavior. There is no dependency on
the P-CSCF and no protocol change is required.
[0067] In FIGS. 5-7, an approach is first presented for multiple
registrations that entails modifications to the third stage of a 3G
IMS architecture. Then FIG. 8 advantageously generalizes this
approach by making modifications to the first stage to address a
limitation. First, to re-cap the existing limitation with regard to
supporting multiple registrations in today's IMS specifications.
Consider a scenario when a UE A is in WLAN access and assigned
IP-address-1. UE A is registered in IMS with <IMPU-A, IMPI-A,
IP-address-1>. Then, UE A moves to UMTS network and is assigned
IP-address-2. If UE-A registers with <IMPU-A, IMPI-A,
IP-address-2>, the previous registration is over-ridden.
[0068] In FIGS. 5-7, a recent, but generally-known proposal
addresses supports simultaneous IMS registrations when changing the
IP-CAN by requiring communicating via a new P-CSCF, and means that
a new IP address is assigned. The solution considers the following
situation: UE A is connected through IP-CAN-1 to PCSCF-1. UE A is
assigned IP-address-1 and is registered in IMS. UE A moves to
IP-CAN-2 and is now connected to IMS through PCSCF-2. UE A is now
assigned IP-address-2. Two options are proposed for supporting
simultaneous registrations in such a scenario: (1) Protocol Changes
in UE and S-CSCF--When registering from new IP-CAN-2, UE uses a
"Reg-ID" to help S-CSCF separate different registrations
[0069] When UE-A registers via IP-CAN-2, P-CSCF-2, it includes a
"reg-id" (see draft-ietf-sip-outbound) to help S-CSCF separate
different registrations. Also, if S-CSCF supports simultaneous
registrations, it responds with "supported: outbound".
[0070] S-CSCF-a authenticates and accepts the registration. In case
UE really wants to override the old registration instead of
maintaining simultaneous registrations, the UE simply sends the
subsequent REGISTER message with the same "reg-id". This is shown
below.
[0071] A change should be noted in S-CSCF behaviour--S-CSCF checks
connectivity to the UE via old P-CSCF-1 and IP-CAN-1. S-CSCF checks
connectivity to UE-A via IP-CAN-1, P-CSCF-1 by issuing a NOTIFY
(for the reg-event, possibly with event attribute set to
"shortened" to trigger a re-authentication). This is a change in
S-CSCF behaviour as today the S-CSCF (according to 24.229) would
de-register the UE-A's contact via IP-CAN-1/P-CSCF-1.
[0072] In FIG. 8, a further feature is disclosed that obviates the
need to route through different P-CSCFs, which currently only have
one security mapping for each IMPI. Thus, we propose a solution
below for the P-CSCF to support multiple security mappings for one
IMPI when needed. The issues addressed include letting the P-CSCF
whether UE is requesting simultaneous registrations or not and
informing the UE if the current P-CSCFs does support simultaneous
registrations. Thus, the protocol changes in UE and P-CSCF are as
follows. When registering from new IP-CAN-2, UE uses "mreg" field
in the "Proxy-Require" header to help P-CSCF separate different
security associations for the same IMPI. When the P-CSCF receives
the value "mreg" in "Proxy-Require" header, the P-CSCF that
supports this extension recognizes the need to maintain multiple
security associations for the same UE (IMPI). A P-CSCF that does
not recognize this extension rejects the REGISTER request with a
failure response. On receipt of a failure response, the UE may
re-REGISTER without asking for simultaneous registrations (i.e.,
without the "mreg" field in "Proxy-Require" header). Thus, we have
a full solution by combining the approach of FIGS. 5-7 with FIG. 8.
However, this solution depends on whether the P-CSCF in the path is
upgraded to support simultaneous registrations or not.
[0073] Therefore, while the foregoing disclosure shows illustrative
aspects, it should be noted that various changes and modifications
could be made herein without departing from the scope of the
described aspects as defined by the appended claims. Furthermore,
although elements of the described aspects may be described or
claimed in the singular, the plural is contemplated unless
limitation to the singular is explicitly stated.
[0074] In addition, while a particular feature may have been
disclosed with respect to only one of several implementations, such
feature may be combined with one or more other features of the
other implementations as may be desired and advantageous for any
given or particular application. To the extent that the terms
"includes," and "including" and variants thereof are used in either
the detailed description or the claims, these terms are intended to
be inclusive in a manner similar to the term "comprising."
Furthermore, the term "or" as used in either the detailed
description of the claims is meant to be a "non-exclusive or".
[0075] Furthermore, although elements of the described aspects
and/or versions may be described or claimed in the singular, the
plural is contemplated unless limitation to the singular is
explicitly stated. Additionally, all or a portion of any aspect
and/or version may be utilized with all or a portion of any other
aspect and/or version, unless stated otherwise.
* * * * *